The present invention pertains generally to plasmas and more specifically to devices for generating thermonuclear neutrons.
Prior art methods for generating hot plasmas have been limited to inertially and magnetically confined systems. A typical example of an inertially confined system is the implosion of fuel microcapsules by impingent high power laser or electron beams. Typical examples of magnetically confined systems comprise theta-pinch devices, Z-pinch devices, various toroidal configurations such as stellarators, syllacs tokomacs, and toroidal Z-pinch devices, which form a magnetic bottle to confine a hot plasma for a predetermined period at sufficiently high temperatures and pressures to produce thermonuclear neutrons.
Both the inertially confined systems and the magnetically confined systems have various disadvantages and limitations. In both types of systems it is difficult and expensive to bring to bear sufficient energy on the hot plasma to insure significant thermonuclear burn. End losses in linear theta-pinch devices and various instabilities defeating confinement in other magnetic confinement systems due to rapid growth relative to containment times, also result in limited burn of the thermonuclear plasma. Damage to inertial confinement targets prior to implosion due to deposition of beam energy directly on the fuel element also limits neutron yield. This has been alleviated somewhat by pulse shaping and limiting the duration of the beam pulse. However, these measures impose extreme design limitations on the beam pulse generator which typically reduce efficiency. Moreover, the necessity of beam focusing to fuel microcapsule diameters requires expensive and easily damaged optics. Additionally, absorption characteristics of fuel microcapsule for impingent laser beams does not provide a good impedance match to insure maximum deposition of energy. Although magnetic confinement systems protect the containment vessel by magnetic energy fields and provide a means for recovering magnetic energy during fuel expansion, such systems are not inherent to inertially confined systems and must be added separately.